Sandell Tiril, Ringstad Geir Andre, Eide Per Kristian
Department of Neurosurgery, Oslo University Hospital Rikshospitalet, Pb 4950, Nydalen, N-0424, Oslo, Norway,
Acta Neurochir (Wien). 2014 Oct;156(10):1901-9; discussion 1909. doi: 10.1007/s00701-014-2171-0. Epub 2014 Jul 10.
Microvascular decompression (MVD) is a documented effective treatment of trigeminal neuralgia (TN). Lately, reports on endoscopy-assisted microvascular decompression (eaMVD) with better outcome and less risk have emerged. This study was undertaken to verify under which circumstances the endoscope proved essential in identifying the neurovascular conflict (NVC) during eaMVD for TN, and to assess the possibility to predict the need for the endoscope on preoperative magnetic resonance imaging (MRI).
Retrospective analysis of 97 patients with TN undergoing eaMVD at the Oslo University Hospital - Rikshospitalet, 1999-2009. To assess the NVC and anatomical variations, surgical reports were evaluated. MRI was available in 66 patients. The MRIs were evaluated by a blinded neuroradiologist.
In 27 of the 97 patients (27.8 %), the endoscope was a significant aid in identifying the NVC, due to a bony ridge obscuring the view of the fifth nerve, a very distal vascular compression, or a combination of both. The preoperative MRI over-diagnosed the presence of a bony ridge. However, the MRI-based fraction of microscopically visible trigeminal nerve (FVN) in the cerebellopontine angle cistern proved diagnostic (ROC curve, AUC 0.89, p = <0.001) with an optimal cut-off value of 0.35. Hence, if less than 35 % of the trigeminal nerve is visible on preoperative MRI, the endoscope will be needed to identify the NVC.
The endoscope is a valuable tool during MVD for TN, especially under anatomical circumstances such as a bony ridge hiding the direct microscopic view of the NVC. These anatomical circumstances can be predicted with good accuracy on preoperative MRI.
微血管减压术（MVD）是一种已被证实有效的三叉神经痛（TN）治疗方法。最近，有关内镜辅助微血管减压术（eaMVD）疗效更佳且风险更低的报道不断涌现。本研究旨在验证在eaMVD治疗TN过程中，内镜在何种情况下对于识别神经血管冲突（NVC）至关重要，并评估术前磁共振成像（MRI）预测是否需要使用内镜的可能性。
对1999年至2009年在奥斯陆大学医院-里克斯医院接受eaMVD治疗的97例TN患者进行回顾性分析。通过评估手术报告来评估NVC和解剖变异情况。66例患者有MRI资料。由一名不知情的神经放射科医生对MRI进行评估。
在97例患者中的27例（27.8%），由于骨嵴遮挡了对第五神经的视野、血管压迫位置非常远或两者兼而有之，内镜在识别NVC方面起到了重要辅助作用。术前MRI过度诊断了骨嵴的存在。然而，在脑桥小脑角池内基于MRI的显微镜下可见三叉神经（FVN）比例被证明具有诊断价值（ROC曲线，AUC 0.89，p = <0.001），最佳截断值为0.35。因此，如果术前MRI上可见的三叉神经少于35%时，则需要使用内镜来识别NVC。
在内镜辅助微血管减压术治疗TN的过程中内镜是一种有价值的工具，特别是在诸如骨嵴遮挡了NVC直接显微镜视野等解剖情况下。这些解剖情况在术前MRI上可以得到较高准确性的预测。
